Automatic steering control apparatus for self-propelled vehicles



April 6, 1954 Filed Jan. 23, 1952 5. R. OVSHINSKY AUTOMATIC STEERING CONTROL APPARATUS FOR SELF-PROPELLED VEHICLES 3 Sheets-Sheet l INVENTOR sun F0190 A. OVSH/NSKY ATTORNEY April 6, 1954 Filed Jan. 23, 1952 FIG. .3

S. R. OVSHINSKY AUTOMATIC STEERING CONTROL APPARATUS FOR SELF-PROPELLED VEHICLES 3 Sheets-Sheet 2 INVENTOR J'TAA/FORO A. OVSHI/VSKY A T TORNEV April 1954 s R OVSHINSKY 2,674,331

AUTOMATIC STEERING CONTROL APPARATUS FOR SELF-PROPELLED VEHICLES Filed Jan. 25, 1952 5 Sheets-Sheet 5 INVENTOR JTA/VF'ORD R- OVSHINSKY A 7' TORNEV Patented Apr. 6, 1954 AUTOMATIC STEERING CONTROL APPARA- TUS FOR SELF-PROPELLED VEHICLES Stanford R. Ovshinsky, New Britain, Conn.

Application January 23, 1952, Serial No. 267,865

15 Claims. 1

This invention relates to apparatus for automatically guiding or piloting a self-propelled vehicle.

It is the general aim of the invention to provide steering control apparatus which can be installed on conventional vehicles without requiring a major modification of the vehicle and which will be operable to pilot the vehicle over predetermined areas of operation and along preselected courses.

A more specific object is to provide a pilot or control unit for a vehicle operable to guide the vehicle along preselected courses, to turn the vehicle from one course to another at preselected locations, and to stop the vehicle after the same has completed its travel over a predetermined area.

A further object of the invention is to provide a control unit having the foregoing characteristics and which is entirely self-operated so as not to require remotely positioned operating or control means and so as not to require an attendant or operator after thevehicle has been started upon a cycle of operation.

Other objects and features will become apparent to those skilled in the art from the following description of the annexed drawings, which, by way of preferred example only, illustrate one specific embodiment of the invention.

In the drawings:

Fig. 1 is a plan view of a tractor upon which the automatic steering control mechanism of the present invention is installed;

Fig. 2 is a side elevational view of the tractor shown in Fig. 1;

Fig. 3 is a side elevational view of the switch assemblage which is operable in response to movement of the tractor over a preselected distance to alter the course of the tractor;

Fig. 4 is a combined end and sectional view of the assemblage shown in Fig. 3 as indicated by the line l l of Fig. 3;

Fig. 5 is a vertical sectional view through the assemblage as indicated by the line 5-5 of Fig. 3;

Fig. 6 is a transverse sectional view through the steering column of the tractor as shown by the line 5-6 of Fig. 1;

Fig. 7 is a top plan view of the switch control drum included in the assemblage shown in Fig. 3;

Fig. 8 is a wiring diagram for the steering control mechanism; and

Fig. 9 is a diagrammatic view of a field over which the tractor may be automatically piloted.

For purposes of illustration, the control apparatus of the present invention is shown mounted upon a conventional tractor l0. Let it be assumed that the tractor is to be utilized in the performance of an operation upon a field P (Fig. 9) wherein it is desired to automatically pilot the tractor from a starting position X to a finish position Y following the course indicated by the broken line. It will be seen that the tractor, from the position X, should be guided in a substantially straight course parallel to the lefthand boundary of the field until a position P, adjacent the upper end of the field, has been reached at which time the tractor should be turned to the right. Thereafter the tractor should be headed toward the lower end of the field to a point P and then turned 180 to the left. The same operational pattern should be followed until the field has been traversed from left to right and the tractor has arrived at position Y.

By way of background, it should be understood that the tractor is to be headed in the desired direction at the starting position X, the engine started, the control apparatu of the present invention started upon a cycle of operation, and then the tractor is to be clutched into movement to be automatically piloted over the outlined course to the finish position Y, at which position operation of the tractor is to be automatically stopped.

The automatic control or pilot apparatus of the present invention comprises generally a gyroscopic unit A for direction sensitive control of a steering motor B while the tractor moves across the field and a switch assemblage C for travel sensitive control of the motor B to effect the 180 turns at the upper and lower ends of the field. In the drawings the gyro unit A is shown mounted on top of the tractor hood, the steering motor 13 disposed to the side of the conventional drivers seat and the switch assemblage C is mounted within a housing D at one side of the engine. In. addition, a control cabinet or panel E housing switches and relays utilized by the apparatus is disposed adjacent and above the housing D. It will be noted that with the apparatus mounted in the aforedescribed manner, the tractor can, if

desired, be driven by an operator seated in the usual position.

In the following description of the control apparatus and its operation, there will be frequent references to the wiring diagram (Fig. 8) wherein there are shown schematic illustrations of conventional switches and relays and other elements utilized in the apparatus. Some of these elements are not otherwise shown nor specifically described since the details of their construction form no part of the present invenby clutch unit 33 and gear train 34.

3 tion and since these elements are commercially available in many forms and models. For example, a conventional generator N (Fig. 8) driven by the tractor engine is utilized to furnish power for the control apparatus.

The generator is placed into circuit relation with the control apparatus when a start button l2 (disposed within the control cabinet or panel E) is closed by the operator to start thecontrol apparatus upon a cycle of operation. Closing of the circuit by means of the button It energizes a relay |3 which causes the gyroscopic unit A to start operation. As will be seen in Fig. 8, the gyro relay |3 remains energized throughout the complete cycle of operation.

However, as previously mentioned, the gyro unit A is utilized to effect direction sensitive control of the reversible steering motor B only during the time the tractor crosses the field. Gyroscopic or direction sensitive operation is effected in a conventional manner, 1. e.,'a gyroscope included in the unit is utilized to actuate servo means. In the present installation, the servo means comprise switches I4 and I5 (Fig. 8) which are selectively closed by the gyroscope to complete circuits between the generator H and relays I6 and H, respectively. The relay l6 when energized will energize reversible steering motor B for a righthand turn and the .relay when energized will energize steering motor B for a lefthand turn. Accordingly, after the tractor has been properly headed at the starting position X and the gyro unit adjusted to correct to the tractor heading or to 180 of the heading in accordance with conventional practice, the tractor can be started into operation with every assurance that the tractor heading will be corrected tothe proper course during travel of the tractor back and forth across the field. For example, if the tractor drifts toward the left the gyro will cause servo switch M to be closed thereby energizing relay l6 which causes steering motor B to effect a right turn back toward the proper heading and course. Thus the tractor will follow a substantially straight track across the field, being constantly corrected to the left and right by the gyro unit A.

The travel sensitive switch assemblage C is operated in response to movement of the tractor so as to be operable when the tractor reaches the points P or P to control the steering motor B through a 180 turn to the right or left. The means for driving the switch assemblage in response to travel of the tractor includes a drive wheel suspended by a conventional oleo support 2| beneath the tractor so as to ride upon the surface of the field. A sprocket 22 is corotatably mounted with the wheel 26 and by means of chain 23 drives a sprocket 24 fixed to the input shaft 25 of a conventional variable speed control unit 26.

An output shaft 21 from the unit 26 is con nected by coupling 28 to drive shaft 29. The drive shaft 29is adapted to be drivingly interconnected to driven shaft 30 for rotation thereof in one direction by a clutch unit 3| and gear train 32 or for rotation in the oppositedirection The details of the clutch units 3| and 33 are not'important to an understanding of the present invention,

but it should be understood that said clutches are arranged to be selectively engaged by solenoids 35 and '36, respectively. For greater understanding of the invention'let it be-said'that when solenoid'35 is energized the driven shaft .the tractor.

3|! is rotated in a forward direction and when solenoid 36 is energized the driven shaft 30 is rotated in a reverse direction.

The driven shaft 30 is rotatably supported by brackets 40 within housing D and the shaft axially supports and rotates a switch control drum 4| fabricated from plastic or other nonconducting material.

As will be apparent from the foregoing description the drum 4| will be rotated when either of the clutches 3| or 33 are engaged and when the tractor is moving so that drive wheel 20 is turned. The amount of drum rotation of course depends upon the distances traveled by The relationship between drum rotation anddistance of travel can be preselected by manually adjusting or pre-setting the speed control unit 26. Accordingly, the drum can be provided with calibrations 42 corresponding to lineal measurements of tractor travel and the passage of said calibrations past a point of reference will serve to record the distance traveled by the tractor.

.In order to recordv or make use of the travel information carried by the drum, an electric switch arm or probe is used as the point of reference, the probe being carried by a nut 5| on threaded shaft 52 with its tip 5.3 engaging the periphery of the drum. A pair of electrical contact strips 54 and 55 are-placed on the periphery of the drum so as to be engageable with the tip on the probe. The strips are out to scale to conform to the upper and lower ends of the field F, the edge 56 on strip 54 conforming to a line .drawn through the points P on the field and the edge 5! on strip 55 conforming to a line through the points P. The strips are separated on the drum 4| a distance determined by the calibrations 42 corresponding to the lineal distances on the field F separating the points P and P. When the tractor is in the starting position if the tip of probe 50 should engage the drum at the righthand end thereof adjacent the edge 56 onstrip 54.

When the control circuit (Fig. 8) is closed by the start button |2 .to energize the gyro relay 3, a-normally open switch |3a in said relay is closed. The switch |3a is in circuit with a switch button 60 and relay 6| and the generator The button 60 is arranged to close with button |2 whereupon relay 6| is energized by the generator. The relay 6| has one normally open switch 6|a which is closed when the relay is energized. Relay |3 has a second normally open switch |.3b which is closed upon energizing relay l3. Switches I32) and 6|a shunt start buttons l2 and 60, respectively, from the circuit so that said buttons can be released to return to their normal open positions and the relays l3 and 6| will remain energized.

Relay 6| has a second normally open switch 6| b connected in circuit with generator H and clutch solenoid 35, said switch being closed upon relay 6| becoming energized whereby clutch solenoid 35 will be energized to cause forward turning movement of the switch control drum 4| when the tractor is moved along the field. Upon clutching the tractor into forward movement from the starting position X, the drum will be rotated forwardly, or counterclockwise as viewed in Fig. 4, so that conductive strip 54 will move away from probe 50 and strip 55 will be moved toward engagement with the probe tip '53. Thus, during movement of the tractor across the field F, the probe 50 is out of engagement with the switch contact strips 54 and 55 as shown in Fig. 8.

When the tractor has traversed the field under steering control of the gyro and has arrived at the turning position P, the probe will engage strip placing relay 62 in circuit with generator ll. When relay 62 is energized a normally closed switch 62a therein will be opened and a normally open switch 521) will be closed. Switch 62a is in circuit with the generator H and relay BI and when opened, relay H is de-energized causing the clutch solenoid 35 to be tie-energized, thus stopping rotation of the switch control drum 4!. Switch 62b is in circuit with relay it and when closed energizes said relay to excite steering motor B to effect a right turn of the tractor.

The steering motor B as shown in Fig. 1 is drivingly connected by chain and sprocket means 63 to the steering column M of the tractor whereby the steering column turned to the right or left corresponding to rotation of the steering motor drive shaft. Adjustably fixed to the steerirg column 64 are a pair of dogs and 6% engageable, respectively, with limit switches 87 and 12 (Fig. 6).

As above stated, the tractor will be turned to the right when probe 59 engages strip 55. The amount of right turn imparted to the steering column is limited by limit switch 67 which is engaged by dog 65 and shifted out of the normal position shown in Fig. 8 to a position wherein the motor relay l6 effecting the right turn is placed in closed circuit with a time delay relay 63 which is thereby energized by the generator 1 l.

The time delay relay 68 performs a plurality of functions. A principal function is to prevent the gyro unit from exercising steering control of the tractor. This function is performed by a normally closed switch 68a operated by the relay and in circuit with steering motor relay H which energizes the motor 13 for a left turn. The switch 68a is opened by the time delay relay 68 for the preselected time period to assure that the steering motor cannot be energized for a left turn by the gyro means until the right turn has been completed. At the end of the time period switch 68a is closed permitting a left turn correction by the gyro unit at which time the 180 right turn will have been completed.

Also during the time delay, the relay opens switch 680 in circuit with relay it to prevent right turning operation of the motor and steering column beyond the position where limit switch 6! is engaged.

A forther function of the time delay relay (i8 is to energize an indexing motor M which drives threaded shaft 522 to shift the nut 51! and probe 58 longitudinally of the indexing drum fill. As will be apparent from Figs. 3 and 7 probe 5!! should be shifted along the drum to correspond to lateral positions assumed by the tractor at the completion of the 189 turns. To effect movement of the nut and probe from right to left along the drum, the nut secured against rotation by guide bars ii! and the threaded shaft 52 is rotated as by the indexing motor S9. The mean for energizing said motor comprises a switch 6811 held closed by relay 58 during its time period, the swi ch 8812 being in circuit with generator ii and indexing motor 653. When the time period ends switch 53?) opens and the probe 50 is disposed relative to the drum and conducting strips in a position corresponding to the position of the tractor relative to the field F at the completion of a 180 turn.

A fourth function of the time relay delay 68 occurs at the end of the time period. Then said relay closes a switch 63d connected in circuit with a relay T5 and the generator II. The relay 15 when energized closes a holding switch 15a to maintain the circuit connection between the relay ?5 and the generator after the switch 680 is opened. The relay '65 also closes a normally open switch 15b connected in circuit with generator ii and clutch solenoid 35. At the same time a normally closed switch 350 is opened by the relay i5 de-energizing relay Eil thereby preventing energization of the clutch solenoid 35. As previously mentioned, clutch solenoid 36 engages clutch 33 to cause reverse rotation of the switch control drum 5 1. Therefore, as the tractor moves from the upper end of the field at the completion of the 180 right turn, the switch control drum il will be rotated in a reverse direction so as to move conductive strip 55 away from the probe 50 and to advance conductive strip 5% toward the probe Eli. During said movement across the field from the upper end to the lower end thereof the gyroscopic unit A will exercise control of the steering motor B in the manner previously described.

When the tractor arrives at a position P adjacent the lower end cf the field the probe 50 will engage conductive strip 5% to place relay [6 (Fig. 8) in circuit relation with the generator H. When relay 1% is energized it operates to close a normally open switch 15a to energize steering motor relay if to cause a left turn of the tractor. Relay it also operates to open a normally closed switch ltb in circuit with the relay 15 thereby causing clutch solenoid 36 to be de-energized and again neutralizing the drum or stopping rotation thereof.

The steering column of the tractor will be turned to the left under control of the relay IT until the dog 66 on the tractor steering column 64 engages limit switch 72 which is shifted to a position (Fig. 8) placing time delay relay H in circuit relation with the relay IT and the generator ll. The time deiay relay 'ii performs a plurality of functions one being to prevent the gyro unit from exercising steering control of the tractor while the same is being guided through a 180 left turn at the lower end of the field. This is accomplished by a, normally closed switch 71a operated by the time delay relay H and in circuit with the steering motor relay H5. The switch Ha is opened by the time delay relay 1! for the preselected time period to assure that the steering motor cannot be energized for a right turn by the gyro means until the 180 left turn has been completed. Also during the time delay, switch We is opened in circuit with relay H to prevent further turning movement of the steering motor and steering column toward the left. At the end of the time period, switch Ila is closed permitting a right turn correction by the gyro unit at which time the 180 left turn has been completed.

Another function of the time delay relay I1 is to energize the probe indexing motor 69 during the time period. This is accomplished by closing a normally open switch .lb connected in circuit with the indexing motor 69 and the generator H. The probe 59 is then shifted along the drum during the time period in the manner previously described in connection with the description of the operation of the time delay relay 58.

A fourth function of the time delay relay l1 occurs at the end of the timeperiod when said relay closes a normally open switch Tld connected in circuit with the relayfil. The relay 6!, as previously mentioned, when energized closes a holding switch 6 la thereby permitting switch Tld to open. As described above, the relay Bl causes clutch solenoid 35 to become energized engaging clutch 3i so as to permit forward rotation of the switch control drum when the tractor moves across the field from the lower end to the upper end.

In summary then, the operation of the automatic steering control or pilot apparatus proceeds along the following lines. The tractor is aligned with the edge of the field in a starting position adjacent the lower end of the field and the tractor engine is started. Thereafter, the start button for the control apparatus is depressed to energize the gyro unit and to engage the switch control drum clutch to permit forward rotation of the drum when the tractor moves across the field. In movement across the field from the lower end to the upper end the gyro unit exercises steering control to pilot the tractor in a substantially straight line. When the tractor reaches a turning position adjacent the upper end of the field the switch control drum, which has rotated in response to movement of the tractor, causes engagement of switch means which start the tractor in a right turn and neutralizes the control drum. In the right turn of the tractor at the upper end of the field, a limit switch is closed to prevent gyroscopic control of the tractor for a preselected time period during which the tractor completes a 180 right turn. At the completion of the right turn switch means are operated to engage clutch means for reverse movement of the control drum and to reinstate steering control in the gyroscopic unit. The tractor then moves toward the lower end of the field and the aforedescribed cycle of operation is repeated.

Thus, the tractor is automatically piloted over the field until the same arrives at the finish position Y. At the finish position, the control apparatus operates switch means to shut off the tractor ignition and to open the circuit to the control apparatus whereby the tractor will remain standing in the finish position. Said switch means comprises a limit switch 80 (Figs. 3, 7 and :8) which is engageable by an adjustable bolt 8! carried by the probe nut 5 I. As previously mentioned, the nut and probe are indexed longitudinally along the control drumfrom right to left as viewed in Figs. 3 and 7 and when the tractor reaches a position on the righthand side of the field the bolt 8! will engage limit switch 80 to open the same and as previously mentioned, switch means operable by said limit switch can be utilized to cut the tractor ignition.

A manually operable normally closed switch 85 is included in the control circuit (Fig. 8) to be operated in case of emergency to open the control circuit and prevent further operation of the automatic control apparatus. It is contemplated that this switch will be utilized by the attendant in testing the operation of the control apparatus.

It should be understood from the foregoing description that there is provided in accordance with the present invention controlapparatus for automatically guiding or piloting a vehicle such as a tractor over preselected courses throughout a predetermined area of operation. It will be advisable in mostinstances .to survey the area of operation .quite carefully. For example, a farmer operating a tractor in a field such as the field illustrated inFigLQ should carefully survey the dimensions of his field so that the contact members 54 and 55 can be accurately fabricated and assembled on the switch control drum 4| to assure accuracy in steering control of the tractor throughout the cycle of operation.

It should be also understood that the aforedescribed mechanism includes elements which can be replaced by equivalents without diminishing the operational characteristics of the control apparatus. For example, the reversible steering motor B can be replaced by a constantly operating motor having clutch means engageable to effect right or left turning movement of the steering column. It is also contemplated that the steering motor can be eliminated and power means drivingly connected to the tractor steering column, the power means to be driven from the tractor engine as for example by a belt and pulley arrangement connected to the tractor drive shaft. As a further example, the generator ll utilized to supply the power to the control apparatus can be replaced by a battery to supply electrical energy to the system. As a still further example, the illustrated drive for the control drum may be replaced by drive means operated from the tractor drive shaft.

Furthermore, it should be understood that the relays incorporated in the control apparatus can be utilized to operate switches for actuating the hydraulic controls, etc. of agricultural implements driven by the tractor through the field and it should be further understood that the control apparatus of the present invention can be utilized to pilot the tractor or other vehicle through p1'e selected courses which differ from the exemplary course shown in Fig. 9.

I claim as my invention:

1. Anautomatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, electrically operable drive means connected to the steering apparatus of the vehicle and adapted to turnthe vehicle in eitherdirection, conductor means interconnecting said source and said drive means, a direction sensitive control unit including a gyroscope and servo means actuated thereby, said servo means being-electrically connected to said conductor means and adapted to selectively energize the drive'means for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including switch means connected to said conductor means, said switch means being adapted when closed to electrically disconnect said servo means and to energize said drive means for a turn in one direction, and said travel sensitive control unit also including motion transmitting means operatively connected to said switch means and adapted to close said switch means in response to movement of the vehicle over a preselected distance.

2. Anautomatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, electrically operable drive means connected to the steering apparatus of the vehicle and adapted to turn the vehicle in either direction, conductor means interconnecting said source and said drive means, a direction sensitive control unit including a gyroscope and servo means actuated thereby, said servo means comprising switch means connected to said conductor means and adapted to selectively energize the drive means for right andleft turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including a switch connected to said conductor means, said switch being adapted when closed to electrically disconnect said servo switch means and to energize said drive means for a turn in one direction, and said travel sensitive control unit also including motion transmitting means opera tively connected to said switch and adapted to close said switch in response to movement of the vehicle over a preselected distance.

3. An automatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, a reversible electrical motor connected to the steering apparatus of the vehicle to selectively turn the same in either direction, conductor means interconnecting said source and said motor, a direction sensitive control unit including a gyroscope and a plurality of servo switches actuated thereby, said servo switches being connected in circuit with said conductor means and adapted to selectively energize said motor for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including switch means connected in circuit with said conductor means, said switch means being adapted when closed to electrically disconnect said servo switches and to energize said motor for a turn in one direction, and said travel sensitive control unit also including motion transmitting means operatively connected to said switch means and adapted to close said switch means in response to movement of the vehicle over a preselected distance.

4. An automatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, a reversible electrical motor connected to the steering apparatus of the vehicle to selectively turn the same in either direction, conductor means interconnecting said source and said motor, a direction sensitive control unit including a gyroscope and a plurality of servo switches actuated thereby, said servo switches being connected in circuit with said conductor means and adapted to selectively energize said motor for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including switch means connected in circuit with said conductor means, said switch means being adapted when closed to electrically disconnect said servo switches and to energize said motor for a turn in one direction, said switch means including a first contact, a second contact, movable support means for said first contact, and motion transmitting means included in said travel sensitive control unit operatively connected to said support means and adapted to advance said support means toward said second contact in response to movement of the vehicle.

5. A automatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, a reversible electrical motor connected to the steering apparatus of the vehicle to selectively turn the same in either direction, conductor means interconnecting said source and said motor, a direction sensitive control unit including a gyroscope and a plurality of servo switches actuated thereby, said servo switches being connected in circuit with said conductor means and adapted to selectively energize said motor for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including 7 switch means connected in circuit with said conductor means and adapted when closed to electrically disconnect said servo switches and to energize said motor for a turn in one direction, said switch means including a first contact, a rotatable drum mounted adjacent said first contact, a second contact mounted on said drum and engageable with said first contact, and means included in said travel sensitive control unit adapted to close said contacts in response to movement of the vehicle over a preselected distance, said last mentioned means including a drive wheel rotatably supported by the vehicle in engagement with the ground and motion transmitting means interconnecting said drive wheel and said drum.

6. An automatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, electrically operable drive means connected to the steering apparatus of the vehicle and adapted to turn the vehicle in either direction, conductor means interconnecting said source and said drive means, a direction sensitive control unit including a gyroscope and a plurality of servo switches actuated thereby, said servo switches being connected in circuit with said conductor means and adapted to selectively energize said drive means for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including switch means connected in circuit with said conductor means and adapted when closed to electrically disconnect said servo switches and to energize said drive means for a turn in one direction, motion transmitting means included in said travel sensitive control unit and adapted to close said switch means in response to movement of the vehicle over a preselected distance, and limit switch means engageable by the steering apparatus during a turn in said one direction, said limit switch means being connected in circuit with said conductor means and adapted to electrically disconnect said switch means and to re-establish electrical connection of said servo switches.

'7. An automatic pilot for a self-propelled vehicle comprising in combination, a source of electrical energy, a reversible electric motor connected to the steering column of the vehicle to selectively turn the vehicle in either direction, conductor means interconnecting said source and said motor, a direction sensitive control unit including a gyroscope and a plurality of servo switches actuated thereby, said servo switches being connected in circuit with said conductor means and adapted to selectively energize said motor for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including switch means connected in circuit with said conductor means and adapted when closed to electrically disconnect said servo switches and to energize said motor for a turn in one direction, motion transmitting means included in said travel sensitive control unit and adapted to close said switch means in response to movement of the vehicle over a preselected distance, and limit switch means arranged for actuation by the steering column during a turn in said one direction, said limit switch means being connected in circuit with said conductor means and adapted to electrically disconnect said switch means and to re-establish electrical connection of said servo switches.

8. An automatic pilot for a self-propelled vehicle comprising in combination, a source of 11 electrical energy, a reversible electric motor connected to the steering column of the vehicle to selectively turn the vehicle in either direction, conductor means interconnecting said source and said motor, a direction sensitive control unit including a gyroscope and a plurality of servo switches actuated thereby, said servo switches being connected in circuit with said conductor means and adapted to selectively energize said motor for right and left turns in response to deviations of the vehicle from a preselected heading, a travel sensitive control unit including switch means connected in circuit with said conductor means and adapted when closed to electrically disconnect said servo switches and to energize said motor for a turn in one direction, said switch means including a first contact, a rotatable drum mounted adjacent said first contact, a second contact mounted on said drum and engageable with said first contact, means included in said travel sensitive control unit adapted to close said contacts in response to movement of the vehicle over a preselected distance, said means comprising a drive wheel rotatably supported by the vehicle in engagement with the ground and motion transmitting means interconnecting said drive wheel and said drum, and limit switch means arranged for actuation by the steering column during a turn in said one direction, said limit switch means being connected in circuit with said conductor means and adapted to electrically disconnect said switch means and to re-establish electrical connection of said servo switches.

9. Automatic control means for the steering apparatus of a self-propelled vehicle comprising a source of electrical energy, electrically operable drive means connected to the steering apparatus and operable to turn the vehicle, conductor means interconnecting said source and said drive means, a control switch connected in circuit with said conductor means and adapted when closed to energize said drive means, said control switch including a movable member having calibrations corresponding to lineal measurements of vehicle travel and adjustably supporting a first switch contact with reference to the said calibrations, a second switch contact supported for engagement by said first contact, control switch actuating means including drive means responsive to lineal movement or the vehicle, and motion transmitting means interconnecting said last mentioned drive means and said movable member and adapted to advance said first contact toward said second contact during lineal movement of the vehicle whereby said control switch is closed in response to movement of the vehicle over a preselected distance.

10. Automatic control means for the steering apparatus of a self-propelled vehicle comprising a source of electrical energy, electrically operable drive means connected to the steering apparatus and operable to turn the vehicle, conductor means interconnecting said source and said drive means, a control switch connected in circuit with said conductor means and adapted when closed to energize said drive means, said control switch comprising a drum rotatably mounted on the vehicle, a first contact adjustably supported on the periphery of said drum, a second contact supported by the vehicle adjacent the periphery of said drum for engagement by said first contact, control switch actuating means including drive means responsive to lineal movement of the vehicle, and motion transmitting means in- 12 terconnecting said last mentioned drive means and said drum for rotation of the drum during lineal movement of the vehicle whereby said control switch is closed in response to movement of the vehicle over a preselected distance.

11. Automatic .control means for the steering apparatus of a self-propelled vehicle comprising a source or" electrical energy, electrically operable drive means connected to the steering apparatus and operable to turn the vehicle, conductor means interconnecting said source and said drive means, a control switch connected in circuit with said conductor means and adapted when closed to energize said drive means, said control switch comprising a drum rotatably mounted on the vehicle and provided with circumferentially spaced calibrations corresponding to lineal measurements of vehicle travel, a first contact supported by the drum in adjusted positions relative to said calibrations, a second contact sup ported by the vehicle adjacent the periphery of said drum for engagement by said first contact, control switch actuating means includin drive means responsive to lineal movement of the vehicle, and motion transmitting means interconnecting said last mentioned drive means and said drum for rotation of the drum during lineal movement of the vehicle whereby said control switch is closed in response to movement of the vehicle over a preselected distance.

12. Automatic control means for the steering apparatus of a self-propelled vehicle comprising 'a source of electrical energy, electrically operable drive means connected to the steering apparatus and operable to turn the vehicle, conductor means interconnecting said source and said drive means, a control switch connected in circuit with said conductor means and adapted when closed to energize said drive means, said control switch comprising a drum rotatably mounted on the vehicle and provided with .circumferentially spaced calibrations corresponding to lineal measurements of vehicle travel, a first contact supported by the drum in adjusted positions relative to said calibrations, a, second contact supported by the vehicle adjacent the periphery of said drum for engagement by said first contact, control switch actuating means including a drive wheel rotatably supported by the vehicle in engagement with the ground, and motion transmitting means interconnecting said drive wheel and said drum for rotation of the drum during lineal movement of the vehicle whereby said control switch is closed in response to movement of the vehicle over a preselected distance.

13. Automatic control means for the steering apparatus of a self-propelled vehicle comprising a source of electrical energy, electrically operable drive means connected to the steering apparatus and operable to turn the vehicle, conductor means interconnecting said source and said drive means, a control switch connected in circuit with said conductor means and adapted when closed to energize said drive means, said control switch comprising a drum rotatably moruited on the vehicle and provided with circumferentially spaced calibrations corresponding to lineal measurements of vehicle travel, a first contact supported by the drum in adjusted positions relative to said calibrations, a second contact supported by the vehicle adjacent the periphery of said drum for engagement by said first contact, control switch actuating means including drive means responsive to lineal movement of the -vehicle,motion transmitting means interconnecting said last 13 mentioned drive means and said drum, first electrically operable clutch means included in said motion transmitting means adapted when engaged to rotate said drum in one direction thereby to engage said contacts, second electrically operable clutch means included in said motion transmitting means adapted when engaged to retate said drum in the opposite direction, conductor means interconnecting said source and said first and second clutch means, switch means included in said last mentioned conductor means operable when said contacts are closed to disengage said first clutch means, and a limit switch included in said last mentioned conductor means operable by the steering apparatus during a turn of the vehicle to engage said second clutch means.

14. Automatic control means for the steering apparatus of a self-propelled vehicle comprising a source of electrical energy, an electric motor connected to the steering apparatus to turn the vehicle, conductor means interconnecting said source and said motor, a control switch included in said conductor means and adapted when closed to energize said motor, said control switch comprising a drum rotatably mounted on the vehicle, a first contact adjustably supported by said drum, a second contact supported by the vehicle for engagement by said first contact, control switch actuating means including a drive wheel rotatably supported by the Vehicle in engagement with the ground, motion transmitting means interconnecting said drive wheel and said drum, 2. first electrically operable clutch included in said motion transmitting means adapted when engaged to effect rotation of said drum in one direction thereby to engage said contacts, a second electrically operable clutch included in said motion transmitting means adapted when engaged to effect rotation of said drum in the opposite direction, conductor means interconnecting said source and said first and second clutches, switch means included in said last mentioned conductor means operable when said contacts are closed to disengage said first clutch, and a limit switch included in said last mentioned conductor means arranged for actuation by the steering apparatus during a turn of the vehicle and adapted to engage said second clutch.

15. Automatic control means for the steering apparatus of a self-propelled vehicle comprising a source of electrical energy, an electric motor connected to the steering apparatus to turn the vehicle, conductor means interconnecting said source and said motor, a control switch included in said conductor means and adapted when closed to energize said motor, said control switch including a drum rotatably mounted on the vehicle, and provided with circumierentially spaced calibrations corresponding to line-a1 measurements of vehicle travel, a first contact comprising an elongated conductive strip adjustably supported by the drum longitudinally thereof, a lead screw rotatably supported by the vehicle adjacent and parallel to said drum, a second contact adjustably carried by said lead screw for engagement by said first contact, control switch actuating means including a drive Wheel rotatably supported by the vehicle in engagement with the ground, motion transmitting means interconnecting said drive wheel and said drum, a first electrically operable clutch included in said motion transmitting means adapted when engaged to effect rotation of said drum in one direction thereby to engage said contacts, a second electrically operable clutch included in said motion transmitting means adapted when engaged to effect rotation of said drum in the opposite direction, conductor means interconnecting said source to said first and second clutches, switch. means included in the last mentioned conductor means operable when said contacts are closed to disengage said first clutch, a limit switch included in the last mentioned conductor means arranged for actuation by the steering apparatus during a turn of the vehicle and adapted to engage said second clutch, electrically operable drive means connected to said lead screw, and conductor means including switch means interconnecting said source and said drive means, said last mentioned switch means being operable when said limit switch is actuated to energize said drive means thereby to move said second contact along said lead screw.

References Cited in the file Of this patent UNITED STATES PATENTS Number Name Date 1,570,547 Avera Jan. 19, 1926 2,074,251 Braun Mar. 16, 1937 2,176,469 Moueix Oct. 17, 1939 2,317,400 Paulus et al. Apr. 27, 1943 2,321,874 Tandler et al June 15, 1943 2,331,144 Sitter Oct. 5, 1943 2,424,288 Severy July 22, 1947 2,493,755 Ferrill Jan. 10, 1950 2,513,868 Hill July 4, 1950 FOREIGN PATENTS Number Country Date 528,174 Great Britain Oct. 24, 1940 549,674 Great Britain Dec. 2, 1942 

